SPFile and PFile in Oracle Database

Introduction:

In the realm of Oracle Database management, server parameter files (SPFile) and parameter files (PFile) play a crucial role in configuring and customizing database settings. These files are essential for Oracle instances to function optimally. In this blog post, we’ll dive into the differences between SPFile and PFile, explore their significance, and provide syntax examples for managing them on an Oracle Linux environment.

SPFile (Server Parameter File)

The SPFile, or Server Parameter File, is a binary file that stores initialization parameters for an Oracle instance. It offers advantages over the traditional PFile by providing better manageability, security, and dynamic changes. Here’s an overview of its characteristics and importance:

• Binary Format: SPFile is stored in a binary format, making it more compact and efficient compared to the human-readable PFile.
• Dynamic Parameter Changes: SPFile allows dynamic changes to initialization parameters using SQL commands, eliminating the need to restart the database instance.
• Security: SPFile is tamper-resistant, reducing the risk of accidental or malicious modifications.
• Default Location: The default location for SPFile is typically $ORACLE_HOME/dbs/spfile<SID>.ora

After Oracle 9i SPFile was introduced as new feature and by default database is started with SPFile.

Check Oracle database instance is started with SPFile or PFile:

SQL> show parameter pfile;
#or
SQL> show parameter spfile;

#If the Value output Shows:

#(Instance started with SPFile)
NAME                                 TYPE        VALUE
------------------------------------ ----------- ---------------------------------------------------------
spfile                               string      /u01/app/oracle/product/12.2.0.1/db_1/dbs/spfilePROD.ora



#(Blank Means started with PFile)
NAME                                 TYPE        VALUE
------------------------------------ ----------- ---------------------------------------------------------
spfile                               string      

Create SPFile from an existing PFile:

SQL> create spfile from pfile='';
#or
SQL> create spfile='' from pfile='';

Start the Database Instance from SPFile:

SQL> startup spfile='<spfile_location>';

Modifying a Parameter Using SPFile:

SQL> ALTER SYSTEM SET <parameter_name> = <new_value> SCOPE=SPFILE;

PFile (Parameter File)

The PFile, or Parameter File, is a text-based configuration file that contains initialization parameters for an Oracle instance. It lacks some of the advantages of SPFile, it is still widely used and offers its own set of benefits:

• Human-Readable: PFile is in plain text format, making it easy to view, edit, and manage using a text editor.
• Startup Parameter: PFile is used during instance startup to initialize database parameters before the SPFile is read.
• Location: The default location for PFile is $ORACLE_HOME/dbs/init<SID>.ora

Viewing Current Initialization Parameters

SQL> SELECT * FROM V$PARAMETER;

Create PFile from an existing SPFile:

SQL> create pfile='/u01/NewPfile/initPROD.ora' from spfile;
#or
SQL> create pfile='pfile_location>' from spfile='<spfile_location>';

Start the Database Instance from PFile:

sqlplus /nolog
SQL> CONNECT / AS SYSDBA
SQL> STARTUP PFILE='<pfile_location>';

In Oracle Database management on Linux, understanding the differences between SPFile and PFile is essential. SPFile provides dynamic changes and security benefits, PFile provides human-readable configurations and is used during instance startup. By mastering the syntax and usage of these files, you can effectively manage and fine-tune your Oracle instances to meet your organization’s requirements.
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